CharDeeMcDenniz already pointed out that if the players really were flaming and being toxic in chat, they would very likely be punished if you reported them. Depending on the severity of their flame, a punishment may not be immediately incurred, but they'd definitely be closer to one - provided you reported them.
As for your punishment, look at it this way: From what information I've seen, the Leaving the Game/AFK report option may be more-or-less redundant. The LeaverBuster System automatically tracks when players leave or stop playing the game, and seems to automatically dish out appropriate punishments as well.
I could be wrong, though - I genuinely know fuck-all about LeaverBuster, so it may very well require reports to be made for the leave/AFK to be flagged and punished. But, regardless, the idea is there - there's a low likelihood that the other players' reports actually did anything to you. As long as you didn't flame them back or anything, you should be fine.
It's also worth noting that, when I say "you should be fine", I'm not considering Lower Priority Queue to be a main punishment. While I've read that it can potentially lead up to a ban, I've never seen such cases, and the real punishments (Chat Restrictions/Account Suspensions) notably differ from LPQ in that they strip Honor.
(I could also be wrong about LPQ not stripping Honor - I haven't suffered an LPQ penalty, but, hey. If I'm wrong, I'm wrong.)
